The present invention relates to burnable insect control delivery devices, and more particularly to an insect control coil such as a mosquito coil.
Insect control coils typically have a spiral-shaped body with is composed of a slowly burnable solid material that contains an insect control active ingredient such as a repellant, an insecticide, or an insect growth regulator that is distributed uniformly throughout the body. When the coil burns, heat vaporizes and disperses the insect control active ingredient.
Insect control coils are well known in the art, and such coils are known to contain various compositions and ingredients. One particular type of coil is shown in U.S. Pat. Nos. 5,657,574 and 5,948,424 which is designed to provide quick coverage for room or other environment that previously was devoid of insect control active ingredient. In these coils, the radially outward tip region has a cross-sectional area that is greater than the cross-sectional area of the inner tail region which results in a dispersion of the insect control active ingredient at a greater rate during initial burning of the coil. Although effective, a consumer using such a coil has no way of knowing or confirming that the coil is providing the fast acting initial dose of active released into the environment, other than, perhaps, the simple observation of the greater size of the end of the coil.
The present invention provides an insect control coil that disperses an initial burst or quick release of a high concentration of insect control active ingredient into the environment to provide a fast acting initial dose. In order to accomplish this, the insect control coil includes a spiral-shaped body composed of a burnable material having an insect control active substance as an ingredient thereof, and a coating on the spiral-shaped body which contains an auxiliary amount of an insect control active substance which provides an auxiliary burst of active substance when burnt. The coating may be formed on the tip end of the body, or alternately, may be formed intermittently along the length of the body of the coil.
In a second embodiment, the coil also includes a sensory cue indicative of the release of the active substance from the coating. The sensory cue may be a component of either the body of the coil or the coating itself.
The sensory cue is used as an indicator for advising a user that the auxiliary amount of insect control active substance contained in the coating is being released into the environment. The sensory cue may be of various types, but preferably is a visual, audible or aromatic cue. For example, the coating could be a different color from the color of the body of the coil itself, and thus result in a coating that looks different on the coil. Another visual indicator could be the addition of a higher amount of oxidizing agent in the coating so that when the coating burns, it sparkles. Likewise, the coating could be composed of materials which would give off a specific color of smoke, i.e. red, white, black, etc. during the initial burst or release of the active ingredient. An audible cue may comprise a hissing sound or a popping sound. Finally, aromatic cues could comprise a fragrance or other specific odor.